An audio signal is a quite common signal processed or output by an electronic device. In addition, with the development of electronic technologies, there are increasing types of audio signals processed or output by an electronic device, for example, a voice signal, a ringback tone, a standard ringtone, an abnormal ringtone, a dual tone multiple frequency (DTMF) signal, and a frequency-shift keying (FSK) signal.
Because of the increasing types of the audio signals processed or output by the electronic device, the audio signal definitely needs to be detected, so as to obtain a detection result of the audio signal, for example, to obtain a type or a characteristic of a to-be-detected audio signal. However, currently, an audio signal cannot be detected in the communications field.